Stacker crane with pivotal fork and extension means thereon



y 1970 P. w. CARPENTER 3,512,672

STACKER CRANE WITH PIVO'I'AL FORK AND EXTENSION MEANS THEREON Filed July 30, 1968 :iiiHiinm:

United States Patent O 3,512,672 STACKER CRANE WITH PIVOTAL FORK AND EXTENSION MEANS THEREON Peter William Carpenter, West Falls, N.Y., assignor to The Air Preheater Company, Inc., Wellsville, N.Y., a corporation of Delaware Filed July 30, 1968, Ser. No. 748,815 Int. Cl. B65g 47/00 US. Cl. 214-730 1 Claim ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to a crane for stacking articles in and removing stored articles from a Warehouse. Many industries conserve storage space by maintaining storage of articles in systematically arranged racks stacked one above another in a system of rows with aisles therebetween. A stacker crane of the usual type is suspended from overhead tracks between the racks and is arranged to extend toward the floor and to traverse the aisles between racks to place articles on/or remove articles from storage racks in accordance with the wishes of an operator.

Usually it is very difficult to maneuver a crane into the aisles bet-ween spaced racks while carrying a load and place the load on the proper rack without placing and replacing it or inching it along until it is situated in the proper position. Conversely, removing an article from a storage rack is usually difficult and slow because a pallet carrying the article must first be partially placed on the forks of a stacker crane, moved, and then released. Then a second or even a third approach is required to place the pallet completely upon the forks of the stacker crane before it may be moved freely and carried safely to another place for further storage or to a place of use.

SUMMARY OF THE INVENTION The stacker crane of this invention utilizes the normal primary vertical and horizontal movements of a loading device for conventional stacker crane, but in addition is arranged to move a load horizontally a greater distance because of a secondary movement of the load carrying device which may be accomplished simultaneously with the normal horizontal movement so as to conserve time in moving the article from one location to another.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a stacker crane constructed in accordance with the invention,

FIG. 2 is a side elevation illustrating the unique telescopic fork, and

FIG. 3 is a cross section of the telescopic fork as seen from line 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Looking now at FIG. 1 of the drawings the numeral designates a vertical mast of a conventional stacker crane 3,512,672 Patented May 19, 1970 having at its upper end a circular platform 22 supported by the structure 19 for rotary movement about a vertical axis that depends from an overhead trolley 12. The trolley 12 moves on wheels 14 horizontally along the tracks 16 while the tracks 16 are in turn mounted at their ends for lateral movement on wheels 18 which roll along a fixed elevated track means 20. Conventional drive means such as the motor 23 is adapted to rotate the mast about its vertical axis, while means 24 moves it laterally along the tracks 16 and other means '25 is adapted to move the entire assembly along the track 20 in accordance with standard practice.

Mounted upon the mast 10 is a carriage 26 having a load carrying platform vertically movable along the mast 10 by a driving means including a conventional elevator device 32. The carriage 26 includes a fork 28 that may be inserted in a pallet 52 under a load and then lifted vertically on the mast 10 and moved horizontally along tracks 16 and 20 to a given position in a storage rack 46. Conventionally the mast 10 and carriage thereon moves laterally along an aisle between tiered racks with the forks withdrawn while suspended only from tracks 16 and 20. The aisle must therefore be sufficiently wide to enable the mast and carriage with the load thereon to be moved into position closely adjacent the rack in spite of the fact that there may be a slight tilting of the mast and some irregularity in the level of the tiered racks themselves. Thus the load carrying crane cannot be directly adjacent the storage racks, but by placing the forks 28 in a rack carrying the load or pallet 52, moving the forks laterally as far as possible, and then replacing the forks in the rack before again moving them as far as possible, it is quite possible to move most articles through a series of steps or by joggling to a predetermined position on the storage racks.

It is however quite necessary to use several time consuming, independent steps, and it is moreover quite necessary that the aisles be sufliciently wide to enable limited lateral manipulation of the load carried on the forks of the crane to the storage racks. The device of this invention performs the stated operation in a single rapid step in a narrow aisle occupying much less space than usually required of a standard crane.

In accordance with this invention there is carried on the several tines of the forks 28 an extension 35 which can be moved laterally with respect to the fork itself. Thus a load on a pallet carried by the forks 28 may be moved laterally a distance equal to the lateral movement of the forks on the track of the carriage, plus an additional lateral movement due to the extension of the surface 35 which comprises a movable platform of the load. The movable platform thus includes an independent telescopic surface 35 for each tine of the fork. The telescopic surface comprises a U-shaped member having inwardly directed rollers 36 resting on tracks 38 in outwardly facing grooves 54 of each tine of the fork. A roller guide 39 is rotatably mounted at 41 in the telescopic member 35 and adapted to ride in a groove in the upper surface of fork 28 to maintain the surface 35 perfectly centered as it is moved forward or backward. The surface 35 is moved relative to the forks 28 by an actuating means which comprises a fluid motor 42, one end of which is pivotally secured at 56 to the fixed end of each tine 28 while its opposite end is pivotally fixed at 58 to the movable surface 35. Suitable fluid supply ducts (not shown) connect the fluid motor With a supply of fluid under pressure whereby its supply to the fluid motor extends the movable surface 35 outward so that a load thereon may be moved laterally a distance greater than normally possible. Upon reaching its lateral limit as determined by the travel of fluid motor 42 the load thereon may be lowered on to the rack such as that shown at 46 by lowering the carriage on the mast whereby the load will be supported by the rack and the movable extension 35 may be withdrawn. Subsequently, the forks 28 are withdrawn from the pallet until there is no interference of the withdrawn forks with the storage rack at either side of the aisle. At this point the entire mast is moved on the overhead tracks down the aisle to a succeeding location where it is again used to either place a load upon the storage rack or to withdraw a load therefrom in the manner above defined.

The stacking crane may thus be used to either place an article on the racks or to remove a stored article therefrom, dependent only upon the will of the operator in cab 48 who controls the position of forks 28 by proper actuation of the driving means.

In order that the forks may be used on both sides of an aisle without rotary or lateral adjustment of the mast, a double flip type fork is provided. This fork comprises two sets of tines arranged substantially normal to one another about a pivot rod 37 in accordance with FIG. 2 of the drawing. Turning of the pivot rod about its axis and actuation of either set of forks to a horizontal position may be made by either manual or power driven means in the cab 48 (not shown). By this arrangement the fork is adapted to project horizontally into the space between tiered racks at either side of the mast without movement of the mast, and either place an article on the rack or remove an article therefrom as determined by the operator.

The control panel in cab 48 is movable vertically up or down the mast 10 along with carriage 26. The cab 48 houses an operator who has access to the control panel for the various motors that control the disposition of the stacker crane. Thus an operator is able to move the lifting device to any spot in a given area and to any vertical elevation with respect to the mast in a minimum of time while utilizing a minimum of space.

While this invention has been described with reference to the accompanying drawings it is readily understood by those skilled in the art that it permits modification within the scope of the appended claim.

I claim:

1. A crane for moving a load both horizontally and vertically comprising in combination an elevated track, a vertically disposed mast depending from said track, trolley means for moving the mast horizontally along the track, a carriage including meansfor moving said carriage vertically along the mast, a pair of spaced substantially perpendicular arranged support forks being rigidly interconnected to each other at one end thereof, horizontal pivot means mounted at the interconnected ends, means for selectively pivoting said support forks about said pivot means between two operative positions wherein one set of support forks are in a substantially horizontally load carrying positions and the other set of support forks are disposed in a vertical upright position, means for moving the fork horizontally along the carriage, a telescopic extension carried on the tines of each of the support fork, and hydraulic means on the support fork for extending the tines thereof by actuating the telescopic extension whereby a load carried on the telescopic extension may be moved laterally a distance greater than the lateral movement of the support fork on the carriage the lateral movement of the telescopic extension with respect to the fork is substantially less than the lateral movement of the support fork with respect to the carriage.

References Cited UNITED STATES PATENTS 2,973,878 3/1961 Gibson 214-730 3,092,268 6/1963 Powers 21475 3,175,722 3/ 1965 Paulssen 214--731 3,232,465 1/1966 Romine 214-730 FOREIGN PATENTS 154,013 9/1951 Australia. 1,044,712 11/ 1958 Germany. 1,229,454 ll/ 1966 Germany.

GERALD M. FORLENZA, Primary Examiner R. B. JOHNSON, Assistant Examiner U.S. Cl. X.R. 214-164, 750 

